In the coal industry, calcite (CaCO3) is widely used to prevent explosions, treat acid mine drainage, and absorb acid rain components such as sulfur dioxide released during combustion. We have previously shown that prevalence of occupational lung diseases in coal workers correlates positively with levels of bioavailable iron (BAI) in coals with a decreasing incidence from eastern to western coalmine regions in the U.S. Calcite is commonly present in relatively large amounts in western coals such as those from Utah and Colorado coalmine regions. Calcite prevents iron from becoming bioavailable, and the coals from these coalmine regions are less toxic than eastern coals such as those from Virginia and Kentucky, which contain high levels of BAI and little calcite. Yet, the introduction of calcite as a protective agent in coals containing high BAI has not been investigated. In the present study, we hypothesize that when exposure to coal dust is unavoidable and the ability of technology to further reduce dust levels is limited, calcite is effective in disease prevention. The goals of the present study are to determine the utility of calcite to reduce coal dust toxicity and to develop and transfer technologies for the prevention of occupational lung disease in coal workers. These goals will be simultaneously achieved through multidisciplinary collaboration of Investigators from environmental medicine, mining and engineering, as well as geology. In Aim 1, we will determine the minimal effective doses of calcite in inhibiting BAI-containing coal-induced inflammation in mice. In Aim 2, we will present this novel preventive strategy to our Advisory Committee, which will assist in educating miners, operators, inspectors and regulators, and facilitating technology transfer. In Aim 3, we will develop technologies and conduct field tests for introduction of minimal effective dose of calcite to high BAI-containing coal dust. To ensure a timely technology transfer, in Aim 4, the most promising technologies identified by the present study will be recommended soon after they pass their underground practicality and feasibility tests. We expect to show that introduction of small amounts of calcite to respirable coal is cost-effective and causes no harm. This innovative dust mitigation strategy to reduce dust toxicity does not require sophisticated engineering breakthrough and could prevent occupational lung diseases in underground coal workers.